Some important notes on quercetin. Its health properties by itself are in question, as it's touted as a healthy additive in high concentrations in many popular health-foods marketed products like food and drinks. However the wikipedia itself https://en.wikipedia.org/wiki/Quercetin states that

Following dietary ingestion, quercetin undergoes rapid and extensive metabolism that makes the biological effects presumed from in vitro studies unlikely to apply in vivo.

So in addition to this

Quercetin has also been reported to have estrogenic (female sex hormone like) activities by activating estrogen receptors. Quercetin activates both estrogen receptor alpha (ERα) and beta (ERβ) with binding IC50s of 1015 nM and 113 nM respectively. Hence quercetin is somewhat ERβ selective (9 fold) and is roughly two to three orders of magnitude less potent than the endogenous estrogenic hormone 17β-estradiol.

The conclusion for now by the FDA is

While quercetin supplements have been promoted for the treatment of cancer and various other diseases, there is no evidence that quercetin (via supplements or in food) is useful to treat cancer[35] or any disease. The US FDA has issued warning letters to emphasize that quercetin is neither a defined nutrient nor an antioxidant, cannot be assigned a dietary content level, and is not regulated as a drug to treat any human disease.

If you read the warning label on products containing quercetin you'll notice the daily amount recommended is not that high in comparison to the amounts in single servings, and it should not be used by people with weakened livers or kidneys.

And yes, plagiarism is bad, and I'm glad people are willing to bring this issue to light and help keep an eye on it on steemit.